Relative Sensitivity

서울대학교 화학공정신기술연구소 공정시스템 및 안전연구센터

김 구 회

화학공정의 사고 시나리오 합성 시스템

Automatic Synthesis of Robust Accident Scenarios for Chemical

Processes

Hazard Analysis

Hazard

Identification Accident

Probability Accident Consequence

RISK MANAGEMENT

정성적 추론 정량적 추론

공정내 사고로 인한

손실 발생 위험영향평가기술

가상사고시나리오 사용자의 주관에 의존

평가결과의 다양성 한계

사고시나리오 합성

공정요소 분석

장치거동 분석

물질특성 고려

사고형태 추론

• HAZOP Study

• FMEA

• What-If analysis

• PHA

• FTA

• ETA

• The starting point of analysis

• The direction of inference

• The scope of analysis

전통적인 위험성 평가 방법

• Time consuming

• Labor intensive

• Requiring extensive and multidisciplinary knowledge

• The quality of analysis is dependent on the analyst’ s ability

INFERENCE STRUCTURE using Rule-based method

기존 위험성 평가 방법의 단점

가상 사고 시나리오란?

정성적 안전성평가방법

 미국에서 처음 WCS(Worst Case Scenario) 의 개념 도입

위험영향평가시스템의 입력값으로 가상 사고 시나리오에 따라 결과의 다양성 존 재

 체계적 방법에 따른 시나리오 추론

 공정상태 분석 및 및 발생 강도 고려

제안된 가상사고 시나리오 추론구조

GLOBAL INFERENCE ENGINE

Accident Scenario Knowledge

Base USER

Equipment Screening

Algorithm Equipment Behavior

Analysis Algorithm Accident Scenario Reasoning Algorithm Equipment Property

Knowledge-Base Material Property

Knowledge-Base Process unit

Knowledge-Base

Equipment Property KB

- NAME : Feed line valve

- UNIT ID :

- CONNECTED FROM - CONNECTED TO :

- SAFETY UNITS : Pressure Temperature Flow rate

- MATERIALS :

N/A N/A

CONTROLLER BY VALVE1 PIPE 4

PIPE 3 VALVE

Toluene

- FLOW RATE : 5 kg/s

- TEMPERATURE : 298 K

- PRESSURE : 2 kg/cm²

...

Material knowledge base

사용된 물질 특성

 NFPA rating(N _f , N _r , N _h )

 Heat of combustion

 Flash point

 Boiling point

 MF(NFPA material factor)

 연소열, flash point, boiling point 고려

Material Property KB

NFPA code

• API 750

• Dow & Mond Index

... .

• N

: Health Hazard Rating

• N

: Flammable Hazard Rating

• N

: Reactivity Hazard Rating

HAZARD INDEX

AMMONIA

Nr = 0 Nh = 3 Nf = 1 HC = 8,000

FP = gas BP = -28

EO

Nr = 3 Nh = 3 Nf = 4 HC = 11,700

FP = -4 BP = 51

C3

Nr = 0 Nh = 1 Nf = 4 HC = 19,900

FP = gas BP = -44

HC(Heat of Combustion, Btu/lb) FP(Flash Point, ℉)

BP(Boiling Point, ℉)

1

3 2

W

Flammability (Red) 4:Extremely flammable 3:Highly flammability 2:Flammability

1:Low flammability 0:Not flammable

Health Hazard (Blue) 4:Extremely hazardous 3:Highly hazardous 2:Hazardous

1:Slightly hazardous 0:Not hazardous

Reactivity hazard (Yellow) 4:Severe explosion risk 3:Explosion risk

2:Potentially explosive 1:Not violently reactive 0:Normal stability

Other hazard (if any) W:Do not use water OXY:Oxidizing

♦:Radiation hazard

N _f

N _r 0 1 2 3 4

0 1 1 2 3 4

1 1 1 2 3 4

2 2 2 4 6 9

3 3 3 6 9 12

4 4 4 8 12 16

복합 특성의 고려

(Multi-property matrix)

화학공정에서의 단위공정 분류

CHEMICAL/ENERGY PLANT

Oxidation, Electrolysis, Nitration Esterification, Aminolysis, Sulfonation,

Alkylation, Polymerization

이송,분배공정

분리, 정제공정

냉각, 소각, 열처리, 열가공, 배가스, 폐수,

폐기물 처리공정

원료,부산물, 및 최종생산물의 저장공정 반응시스템

공급시스템

분리시스템 유틸리티시스템

저장시스템

Process Unit KB-1

Chemical Process Unit Classification

Process Unit

-Feed System, Reaction System, Production System, Storage System,

Utility System

Safety Unit -Mitigative Safeguard -Preventive Safeguard

Topography

Meteorological data

Characteristic of surrounding area

Process Unit KB-2

Unit 1

materials

Propane(G) Butane(G)

Water Air

Composition

Stripper Air fan Stripper pump

Number of

Analysis node ⁴

Unit 2

materials

Propane(L) Propane(G) Butane(L) Butane(G)

Composition

Dry tank(3) Heater(2)

Pump(7) Cavern

Number of

Analysis node ¹²

Unit 3

materials

Methanol Odorant Nitrogen

Composition

Storage tank Pump(2)

Number of

Analysis node ⁶

Unit 4

materials

Propane(L) Butane(L)

Composition

Unloading arm Pump(2)

Number of

Analysis node ⁴

Characteristics of Surrounding Area Meteorological Characteristics

가상사고 시나리오 추론단계

Macro Decomposition

(Unit function and topography analysis)

Micro Decomposition (Equipment screening

with equipment knowledge base)

Equipment Behavior Analysis (Root cause and effect reasoning)

Process Unit Selection

Process Equipment Selection

Accident Reasoning

(EFaCRA and material knowledge base)

Accident Scenarios at Given Mode

Accident Scenarios Selection

Effect Analysis Emergency Planning

And Safety Device

Secondary Equipment

Macro Decomposition Algorithm

시나리오 추론과정의 첫번째 단계

 주요 기능시스템의 구분과 정의



Feed system, Reaction system, Production system, Storage system, Utility system

 기후적 특성 고려



평균 풍향 및 풍속

 Topography



인근지역의 주거비, 지리적 환경

 Material



Highly toxic, flammable material

Macro Decomposition Algorithm

Unit

Decomposition

Detailed Analysis

Macro Decomposition Algorithm

Unit 1 Storage unit

Unit 2 Reaction unit

Unit 3 Reaction unit

Unit 4 Storage unit

Unit 5 Utility unit

Unit 6 Utility unit

Wind Direction

Commercial Area

Resident

Area

Wind Direction

Equipment Screening Algorithm

대상공정에 대한 세부요소 분석

 물질의 특성



NFPA rating 3 이상

 운전조건



초고온, 초저온상태



액화가스, 압축가스, 가연성물질에 따라 분류

 유량



공정에 따른 상대적 유량

 안전장치



Preventive safety device

 장치의 연수

 사고사례

Screening 기준

Equipment Screening Engine (Rule-Based)

Chemical Property NFPA rating Combustion of Heat

Flash Point

Operating Condition Pressure

Temperature

Flow Rate

Age

(averaging age) Safety Device

Preventive Device Mitigative Device)

Accident History Repaired History Failure Rate

(yr^-1)

REPAIRED HISTORY

ACCIDENT HISTORY

FAILURE RATE

AGE

SAFETY DEVICE

OPERATING CONDITION

FLOW RATE

MATERIAL PROPERTY

Sequential Reasoning

Consequence Analysis Probability Analysis

기준에 따른 절대값 상대적 지침

Preventive Safeguard Failure Probability

최종 우선순위를 위한 참고지침

Screening guideword의 우선순위에 대한 기준

HIRA(Hazard Identification and Ranking)

 Khan & Abbasi (1998)

 Relative ranking method

 Two Indices:



Fire and Explosion Damage Index (FEDI)



Toxic Damage Index (TDI)

 It provides quantitative scores;



Easy interpretation of results



Comparison of hazards

Relative Sensitivity Analysis

공정변수들이 시나리오 결과에 미치는 영향의 정도를 비교

무차원군으로 표현

± 10% change



Heat of combustion (i.e., material itself)



Operating pressure



Operating temperature



Quantity (or flow rate)

x y x x

y y S

ln ln

∂

= ∂

∂

∂

=

Relative Sensitivity Analysis

- Results

Analysis Results (김, 2000)

물질의 종류/양(유속)이 공정 온도/압력보다 더 민감한 변수

±10% Changes Relative Sensitivity Heat of combustion 0.33 (avg.)

Operating pressure under 10E-4

Operating temperature under 10E-4

Quantity (or flow rate): 0.33 (avg.)

Relative Sensitivity Analysis

- Results

0 0.5

R e la ti v e Se n si ti v ity

Relative Sensitivity A nalysis Results

Hc Temp.

Pres s .

Quan.

Equipment Screening Algorithm

Operating Condition

Flow-rate

Safety Device

Age

Accident History Material Property

액화가스: 2 kg/cm² 이상 압축가스: 10kg/cm² 이상 가연성 액체: 상온 상압 이상

유량5 kg/s 이상

Interlock system이나 비상밸브의 장착 여부

평균수명 이상 되는 장치 여부

유사장치나 공정의 사고 유무 NFPA rating 3 이상

(N_h N_f N_r)

A B C D E F G H I DESCRIPTION

Guideword Component

Equipment Behavior Analysis-1

(Equipment Failure and Cause Reasoning Algorithm)

Qualitative analysis

 장치의 fail 여부에 따른 분석(Forward, Backward)

 각 장치별로 작성

 각 장치의 이상원인과 결과 추론

Property of materials

 Material의 특성에 따른 등급 부여

 Toxicity, Flammability

 NFPA rating

Equipment Behavior Analysis-2

Heat Exchanger, High Pressure

Leak Rupture Fouling

Valve

Open Closed

Rupture Leak

Pump

On Off

Seal Leak/Rupture

Casing Leak/Rupture

Equipment Failure and Cause Reasoning Algorithm(EFaCRA)

Failure Mode

Cause Reasoning(Backward) Effect Reasoning(Forward)

Effect Propagation (Internal/External)

Ultimate Effect (Possible Accidents)

Effect Calculation

Preventive Measure /Emergency Plan Cause analysis for Failure mode

(Internal/External)

Root Cause

Safeguard

Equipment Failure and Cause Reasoning Algorithm(EFaCRA)

Fail Closed (No flow)

Internal

External External

Internal Motor failure

Malfunction

Indicator error Electricity shut-down Sedimentation

Internal high pressure

Rapid eddy

No flow External stream

Back-flow Inlet high flow/pressure

Cause Effect

Corrosion Abrasion Mechanical

error

Sensor failure Abrupt reaction

Impurity upstream

Valve breakage

Downstream failure Downstream

equipment breakage

Root Cause Ultimate Effect

Accident Reasoning Algorithm

ACCIDENT ANALYSIS ALGORITHM

:RULE

Fire...

Personnel Injury Explosion

...

Equipment Damage Toxic Material Release Accident Scenarios

Knowledge Base

Material Property Knowledge Base

Material Hazard

Index Ultimate

Effect EFaCRA

NFPA Rating

Case Study-1

가연성액체 저장 설비 및 loading 설비

 Tank truck으로 부터 가연성액체를 padding 상태로 T-1에 저장

Valve 7개, 저장탱크 1개, 펌프 1개

PICA-1

TIA-1

LIA-1

PI-1

FICA-1

To the next process

FV-1 V-4

P-1 V-3

1”

4”

V-1 1”

From tank truck

RV-1

V-6

PV-2

1”

1” PV-1

V-7 To atmosphere Nitrogen To flare

Flammable Storage Tank T-1

V-2 V-5

Equipment Screening Algorithm

Operating Condition

Flow-rate

Safety Device

Age

Accident History Material Property

액화가스: 2 kg/cm² 이상 압축가스: 10kg/cm² 이상 가연성액체: 상압 이상

유량5 kg/s 이상

Interlock system이나 비상밸브의 장착 여부

평균수명 이상 되는 장치 여부

유사장치나 공정의 사고 유무 NFPA rating 3 이상

(N_h N_f N_r)

V-1 V-3 V-4 V-5 V-6 V-7 PV-1 PV-2 FV-1 DESCRIPTION

Guideword Component

V-2 P-1

Equipment Behavior Analysis Algorithm

Equip. Mode

Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Valve

(V-5) on the feed line

Fail open

Motor failure Malfunction

Sensor failure Electric shut-down

Excess flow of flammable liquid to

the storage tank High level in the

storage tank

May cause tank rupture

due to overpressure

Flam- mable

liquid

A (Fire)

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking

Valve (V-5) on the feed line

Fail closed

Motor failure Malfunction Sensor failure

Electric shut-down

Sedimentation Impurity upstream

No flow of flammable liquid to

the reactor Overpressure of inlet of the pump

P-1

Overpressure of the tank truck

Internal high pressure back-flow to

the Cavern

May cause tank rupture

due to overpressure May cause valve

breakage

Flamm able liquid

Flamm able liquid

A (Equip.d

amage /fire)

A (Equip.d

amage /fire)

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Valve

(V-5) on the feed line

Leak Corrosion

Abrasion Outer impact

Small release of flammable liquid to

the surrounding area

Release of flammable liquid

Flamm able liquid

B (Fire)

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking

Valve (V-5) on the feed line

Rup- Ture

Corrosion

Abrasion Outer impact

Large release of flammable liquid to

the surrounding Area

Release of flammable liquid

Flamm able liquid

A (Fire)

Case Study-2

C3 이송, 저장, 공급시설

 해양의 선박으로부터 공급 받아 지하동굴형 저장시설(cavern)에 저장한 후, 공급

 Cavern, dryer 5개, stripper 2개, odorant storage tank, inhibitor storage tank,

heater 3개, pump 26개, valve 67개 등으로

구성

C3/C4 Storage Tank

Inhibitor Drum

Odorant Drum

C3/C4 Cavern

Dryer

N₂ Storage Tank Air Stripper

C3/C4 Heater

Boosting Pump Unloading Arm

Loading Arm Vent Stack

Air

Stripper pump

Methanol Injection Pump

Odorant Injection Pump C3/C4 transfer Pump

V-1

V-2

V-4 V-3

V-5

V-6

V-7

V-8

V-9 V-10

V-11

V-13 V-12 P-1

P-2

P-3

P-4 P-5

P-6 H-1

A

B C

D E F

G

H

I J

K

L

M

N

C3/C4

Control Room

Utility Area

Education Center Office

Dining &

Rest Room

Power Facility Gate

Unloading Area

SEA

SEA

Cavern Area

Residential Area

Air Comp.

Stream

NO. Fluid Temperature ( C)

Pressure (kg/cm2G)

Flow Rate m3/h (ton/h)

Density (kg/m3)

A C3 Liquid -45 5.0 2000 585

B C3 Liquid -45 3.4 2000 585

C C3 Liquid -45 9.0 2000 585

D C3 Liquid -45 8.9 2000 585

E C3 Liquid 2 7.6 2000 527

F C3 Liquid 8.8 16.7 1568 517

G C3 Liquid 8.8 16.4 608 517

H C3 Liquid 8.8 14.4 608 517

I C3 Gas 5 6.1 - -

J Water

/C3 Gas 7.1 8.3 250 1010

K Water 7.2 0 350 1010

L Nitrogen AMB. 4.0 - -

M MeOH AMB. 24 4.5 0.79

N ROH AMB. 24 0.3 0.84

Operating Condition

Flow-rate

Safety Device

Age

Accident History Material Property

액화가스: 2 kg/cm² 이상 압축가스: 10kg/cm² 이상 가연성액체: 상압 이상

유량600 m³/H 이상

Interlock system이나 비상밸브의 장착 여부

평균수명 이상 되는 장치 여부

유사장치나 공정의 사고 유무 NFPA rating 3 이상

(N_h N_f N_r)

H1 P2 P3 P4 P5 P6 V1 V2 ^V3 DESCRIPTION

Guideword Component

P1 V4 V5 V6 V7 V8 V9 V10 V11 V12 V13

Equip. Mode Cause (Root Cause)

Effect Ultimate

Effect Mat.

Relative Risk Ranking Valve

(V-5) on the line to the dryer

Fail open

Motor failure Malfunction

Sensor failure Low hydraulic

pressure

Electric shut-down

Excess flow of Flammable liquid

to the dryer

High level in the dryer

Overpressure in the dryer

May cause tank rupture due to over-

pressure

C3 (L.G)

A (Fire/Ex -plosion)

Equip. Mode Cause (Root Cause)

Effect Ultimate

Effect Mat.

Relative Risk Ranking Valve (V-

5) on the line to the

dryer

Fail closed

Motor failure Malfunction Sensor failure Low hydraulic

pressure Electric shut-down

No flow of C3 to the dryer tank Low level in the dry

and dry tank Internal high pressure

Rapid eddy Back-flow to cavern

High pressure of outlet pump in the

cavern

Inlet pump fail due to high pressure

May cause tank rupture in the cavern

May cause valve breakage

C3 (L.G)

C3 (L.G)

C (Pump Damage)

A (Fire.Expl

-osion)

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Valve

(V-5) on the line to the dryer

Leak Corrosion

Abrasion Outer impact

Small release Of C3 to the

surrounding area

Release of C3 C3 (L.G)

B (Fire/Ex -plosion)

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Valve

(V-5) on the line to the dryer

Rup- ture

Corrosion Abrasion

Outer impact

Large release of C3 to the surrounding

area

Release of C3 C3 (L.G)

A (Fire/Ex -plosion)

Equip. Mode

Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Heat

exchang er(H-1)

on the feed line to

the cavern

Leak (tube

To shell)

Corrosion

Abrasion

Outer impact

Over flow rate or high pressure of

inlet line

Small release of C3 to the

shell side

Less flow of C3 to the cavern

High pressure of water stream Low pressure of inlet stream to the

cavern

Release of C3 C3 (L.G)

B (Fire/Ex -plosion)

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Heat

exchang er(H-1)

on the feed line to

the cavern

Rup- ture (tube

To shell)

Corrosion Abrasion

Outer impact Over flow rate

or high pressure of

inlet line

Large release of C3 to the

shell side No flow of C3 to

the cavern

High pressure of water stream

May cause shell side rupture due to overpressure

Heat exchange damage

C3 A

(Fire/Ex -plosion)

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Heat

exchang er(H-1)

on the feed line to

the cavern

Leak (tube

To Exter -nall)

Corrosion

Abrasion Outer impact

Small release of water to the

surrounding area

Less flow of water in the

shell side

Lowering function of heat

exchanger

Heat- exchanger

damage

Water -

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Heat

exchang er(H-1)

on the feed line to

the cavern

Rup- ture (tube

To Exter -nal)

Corrosion

Abrasion Outer impact

Large release of water to the

tube area No flow of water in the

shell side Malfunction of

exchanger

Heat- exchanger

damage

Water -

Equip. Mode Cause (Root Cause)

Effect Ultimate

Effect Mat.

Relative Risk Ranking Heat

exchang er(H-1)

on the feed line to

the cavern

Plugg ed (tube side)

Sedimentation Abrupt reaction

Impurity upstream

Outlet valve fail

No flow of C3 to the cavern

Internal high pressure Rapid eddy

Back-flow to the pump (P-1) High pressure

of inlet pump Inlet pump fail

due to high pressure

May cause tube rupture

due to overpressure

Pump and heat exchanger

damage

C3 -

Equip. Mode Cause

(Root Cause) Effect Ultimate

Effect Mat.

Relative Risk Ranking Heat

exchang er(H-1)

on the feed line to

the cavern

Plugg ed (shell

side

Abrupt reaction

Impurity in shell side

Lowering function of heat

exchanger

Heat- exchanger

damage

- -

결론 및 제안사항

Fault tree analysis와 effect analysis와의 연계



Accident probability와 accident consequence analysis로의 확장

Accident Probability

Hazard

Identification Accident Consequence

정량적 추론 정량적 추론

Hazard Analysis

ARA 분석결과의 정량화 가능성

Ultimate effect와 material property의 정량화 Ultimate effect의 고려

 Release of material

 Equipment failure

 Downstream fail

 Upstream fail

각각의 ultimate effect에 대한 penalty

 크기에 따른 penalty(1-5)

Material property에 대한 penalty

 복합 특성 등급 사용(0-16)

Release of material(5) Equipment fail(3) Downstream fail(2)

Upstream fail(2)

C3(4) EO(12)

Am(3) C3(4)

Magnitude of Potential Damage And Possible Accident

물질의 복합특성

Ultimate Effect

Material Property (복합물질 등급 또는 MF)

Release of material Equipment breakage

Upstream fail Downstream fail에 대한

PENALTY

발생가능 사고유형 및 등급 Fire

Explosion Toxic release Equipment damage

이상원인에 대한 상황 및 근본 이상

원인 이상으로 발생 가

능한 상황

Consequence Analysis

Reports

Data 관리

 DataBase

실시간 공정 조업

 Real-Time DB, PFD

공정 설계

 GIS, PFD

공정 관리

 Emergency Planning